In automotive fuel injection systems, the power delivered by the engine is related to the shape of the spray, as well as the quantity and timing of fuel delivered to the combustion chamber.
Various devices for measuring fluid flow characteristics, at various points in the flow, have been described previously. For example:
U.S. Pat. No. 3,338,093, issued Aug. 29, 1967 to J. D. Usry et al. relates to an injectant stream analyzer for measuring the momentum and solidity of fluid free streams from injection valves or the like by causing a wire to transect the stream.
U.S. Pat. No. 3,548,655, issued Dec. 22, 1970 to M. J. Rudd, describes a laser Doppler velocimeter for measuring the velocity of fluid flow which measures the sinusoidal variation in light intensity as a particle in the fluid passes through interference fringes produced by laser beam which passes through a two slit mask. No means for measuring instantaneous velocity is described, nor is velocity necessarily measured on a center line. Further, no processing means for computing volumetric flow rate is described, and no means for indicating the direction of the velocity is described.
U.S. Pat. No. 3,825,346, issued Jul. 23, 1974 to J. Rizzo, reaches an interferometer for measuring fluid flow which uses two earns, a reference beam and a test beam, which travel equal path lengths and recombine to form an interference pattern.
U.S. Pat. No. 3,937,087, issued Feb. 10, 1976 to W. S. Heggie, teaches a transducer for measuring pressure changes during fuel injection. The transducer is a resistive element in the form of a coil wrapped around the fuel line which varies in resistance as the fuel line expands and contracts, the difference in current through the coil being measured through a bridge.
U.S. Pat. No. 4,073,186, issued Feb. 14, 1978 to C. L. Erwin, Jr., describes a flow meter having a magnet mechanically attached to a valve, the magnet generating current in a magnetic pickup as the valve opens and closes for counting the flow pulses, the device releasing metered amounts of fuel with each pulse. The device appears to be for measuring fuel consumption, and not for regulating fuel flow into an injector.
U.S. Pat. No. 4,165,635, issued Aug. 28, 1979 to Komaroff et al. relates to a method of testing fuel-injector spray nozzles in which a laser beam is directed onto a light detector along a path passing close to the spray orifice(s) of a fuel injector spray nozzle.
U.S. Pat. No. 4,192,179, issued Mar. 11, 1980 to E. Yelke, discloses a collar which fits around a fuel line to a fuel injector and has piezoelectric material affixed to the inside surface of the collar to develop an electrical signal as the fuel line expands and contracts.
U.S. Pat. No. 4,541,272, issued Sep. 17, 1985 to Bause relates to an electronically controlled fuel injector system including an electrically controllable injection valve disposed at a suction pipe to supply fuel and an electro-optical spectrometer which analyses the air-fuel mixture sucked in by the engine.
U.S. Pat. No. 5,031,460, issued Jul. 16, 1991 to Kanenobu et al., teaches a device for detecting pressure changes in pipes. The device is a transducer with a bimorph piezoelectric transducer; trapped around the pipe to sense expansion of the pipe as fluid is pulsed through the pipe.
U.S. Pat. No. 6,049,382, issued April 11, 2000 to Lazaro Gomez relates to an apparatus and procedure for characterization of sprays composed by spherical particles, by means of a laser source generating a collimated laser beam that is passed through the spray to be characterized.
German Patent No. DE3817096, published Dec. 8, 1988, relates to a method for testing injection valves and an apparatus for carrying out the method. More particularly, a laser beam penetrating the exit stream of an injection valve underneath its exit opening is captured by a receiver to make a statement about the production quality of the injection valve.
European Patent No. 489,474, published Jun. 10, 1992, describes a laser apparatus for measuring the velocity of a fluid which uses an interferometer type device with a laser beam split into a reference beam and a measurement beam which is reflected back through the fluid so that the back scatter is compared to the reference beam to measure velocity. No method for processing the velocity to compute volumetric flow rate is described.
French Patent No. FR2719871, published Nov. 17, 1995, relates to test equipment for fuel injectors of internal combustion engines. More particularly, the characteristics of a jet of fuel are detected by e.g., a CCD video camera with image processor, a laser granulometer and a display.
Japanese Patent No. 8-121,288, published May 14, 1996, shows a device for measuring injection rate with a pressure sensor for measuring the force of injection and a laser Doppler anemometer for measuring velocity, and which uses a mathematical formula which relates force and velocity to flow rate.
Japanese Patent No. 8-121,289, published May 14, 1996, describes a device which uses two laser Doppler anemometers, one in the main supply line, the other in a bias flow generating unit fed by a divider pipe, to measure the flow rate by a differential flow rate method.
Applicant has co-authored several publications which disclose flow measuring devices. An article titled “Measurement of instantaneous flow rates in periodically operating injection systems” by F. Durst, M. Ismailov, and D. Trimis, published in Experiments in Fluids, Vol. 20, pp. 178-188 in 1996, describes a technique for measuring instantaneous flow rates using laser Doppler anemometry to measure center line velocity in a capillary pipe and an improved solution of the Navier-Stokes equations for any periodically oscillating flow to calculate instantaneous violumetric flow rate. The device measured the flow of water released by a magnetically operated valve through a 2 mm diameter tube.
A paper presented at the Flomeko '98 9th International Conference on Flow Measurement in June, 1998, titled “Accurate LDA Measurements of Instantaneous and Integrated Flow Rates in High pressure Gasoline Injection System” by Ismailov et al., describes device for measuring flow rate in a gasoline injection system at 7 MPa with a Unisia Jecs swirl injector. The device uses a 16 mW He—Ne laser directed through a beam splitter and frequency shifted) Bragg cells, focused by a lens to form a measurement control volume 485 μm in length and 46 μm in diameter on the center line of quartz pipe 300 mm long having an inner diameter of 3.5 mm. The light is scattered by heptane and detected through a pinhole by a photomultiplier tube elevated at a 30°, the output being processed by a DOSTEK interface board. The center line velocities are processed according to the method set forth in Durst, supra.
A paper presented at the 3rd ASME/JSME Joint Fluids Engineering Conference July 18-23, 1999 titled “Instantaneous Flow Rates in Gasoline Direct Injection System By Means of LDA and Bosch Meters” by Ismailov et al., and an article titled “LDA/PDA measurements of instantaneous characteristics in high pressure fuel injection and swirl spray” by Ismailov et al. in Experiments in Fluids, Vol. 27, pp. 1-11 (1999) present similar studies and describe similar measuring devices to those presented in the Flomeko article, supra.
Among those benefits and improvements that have been disclosed, other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying figures. The figures constitute a part of this specification and include illustrative embodiments of the present invention and illustrate various objects and features thereof (of note, similar reference characters denote corresponding features consistently throughout the attached drawings).